Special ink paves the way for cheap polymer solar cells

With a major investment from Innovation Fund Denmark, a consortium of companies and research institutions led by senior researcher Eva Bundgaard from DTU Energy will develop new materials for polymer solar cells.

Polymer solar cells are a promising alternative to tradional silicon solar cells, having the potential of a substantially lower production cost. A polymer solar cell consists of a number of thin layers deposited one by one on a carrier foil using roll-to-roll processes known from the printing industry. Each layer is printed using a particular, highly specialised ink containing the required material. Today, good inks exist for all the layers of the solar cell, except for the important active layer in which the energy of the sun is converted into electrical energy. The lack of an ink for the active layer with the necessary properties, and in the quantities needed industrial production, is a major hindrance to the spread of the technology.

The purpose of the project INKA – Inks for large-scale processing of polymer solar cells is to develop an ink for the printing of the active layer of the solar cell, but also to ensure high compatibility between this ink and industrial printing machines. The research and development will start from the requirements of the solar cell and its manufacture. These requirements are then translated into specific requirements to the composition and print properties of the ink and to the printing machine.

The main result of the project will be a robust ink enabling mass production of polymer solar cells with an efficiency of at least six percent in the conversion of solar energy into electricity. This is more than double the present efficiency. To reach this ambitious goal it is necessary to develop a polymer which efficiently can capture and convert the solar energy to electrical energy, and which can be realised in an industrially printed ink. This means that the polymer must be able to be manufactured in large quantities and with fully scalable methods. Industrial printability also implies automation of the printing process to increase reproducibility and reduce waste.

This will be a significant step towards the development af a competitive industry based on the DTU technology for mass production of polymer solar cells, with applications ranging from consumer electronics to large-scale energy production.